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A convenient, sensitive, and reliable assay for the conversion of radiolabeled sucrose to alcohol-insoluble dextran by the Streptococcus mutans dextransucrase has been developed.

A method to exclude mites and other contaminants from test tube cultures is described. It consists in covering the mouths of the tubes with cigarette paper which is applied by pressing the flamed r...

An acid hydrolysate of casein, vitamin-free casamino acids (Difco), is commonly used as the amino acid source in early phases of nutrition work. Frequently, it is necessary to replace such a complex source with an equivalent, defined mixture of amino acids. This change in the medium often results in longer lag periods and reduced yields. The difference in yields can be the result of incomplete information on the composition of the complex source. The purposes of this paper are to present more complete data on the amino acid composition of and to briefly discuss other organic components of vitamin-free casamino acids (Difco). Amino acids.-A composite amino acid analysis obtained by using paper chromatography is currently available for casamino acids and is given in TABLE I, Column A (personal communication from Mr. V. R. Wheat, Technical Service, Difco; 7 Oct., 1970). The technique of Moore and Stein (1963) provides a more rapid and accurate means of determining the amino acids in a mixture. The samples of casamino acids were stored in a desiccator prior to preparation of the solutions which were analysed on a Beckman-Spinco automatic amino acid analyser (Model 121; Spinco Division, Beckman Instruments, Inc., Palo Alto, California). The techniques used have been previously reported (Nolan, 1970a.). The results of duplicate analyses of three lots of casamino acids are presented in TABLE I (Columns C, D, E). The accuracy of the data within each lot is -+ 5.1% or better. The values for ammonia, cysteic acid and tyrosine were not included in the accuracy calculations either because of susceptibility to external conditions or because the concentrations were too low.

This paper includes a preliminary cost study for producing cocoa butter-like fat from hydrogenated cottonseed oil and triolein at an annual rate of 8.4 million lb in a hypothetical plant, employing interesterification and fractional crystallization as used in pilot plant studies at the Southern Utilization Research and Development Division. Equipment costs, total plant cost, manufacturing costs, and general expenses are given. Operating cost is estimated at 36.9ϕ/lb of product. This includes 31.8ϕ for manufacturing, 4.1ϕ for general expenses, and 1ϕ for refining of the recycled mixture of saturates and unsaturates.

The lactate dehydrogenase isoenzyme pattern of human dental pulps from deciduous teeth and normal and impacted permanent teeth were studied by means of cellulose acetate paper electrophoresis. A dominance of the LDH-3 and LDH-4 isoenzymes was observed. This result is further evidence for the presence of a prominent anaerobic metabolism in this tissue.

Biochemical systematics has provided additional criteria for characterizing taxa already defined by conventional morphological, geographical, ecological, and cytological observations. Paper chromatography has been used for the rapid, efficient separation of relatively small molecules (Alston and Turner, 1963) and zone electrophoresis for relatively large molecules, such as proteins or enzymes (Leone, 1964), to detect meaningful differences or similarities among species within a genus. Clare (1963) separated soluble proteins in mycelial extracts of species of the fungal genus Pythium by zone electrophoresis and obtained patterns which appeared to characterize each species. Meyer et al. (1964) used culture filtrates of strains from 2 species of the fungal genus Fusarium to obtain esterase and phosphatase zymograms. Their reports suggested that zone electrophoresis might provide a useful tool in fungal taxonomy. Raper and Fennell (1965) recently published an extensive revision of the fungal genus Aspergillus. The numerous and apparently well defined species assigned to different groups in this genus offered suitable material to determine whether zymograms might provide an additional method to distinguish species. This report presents the results of a preliminary survey of leucine aminopeptidases, esterases, and phosphatases in mycelial extracts of 15 species of Aspergillus which were detected in starch gels after zone electrophoresis.

Human dentin and bovine skin collagens, partially hydrolyzed with acid, were compared by peptide mapping on thin-layer plates. The patterns, which showed 20 to 25 spots, were similar for the two types of collagen. No major differences in the structural characteristics of dentin and skin collagens can be predicted from these results.

Published work done on a group of selected natural and synthetic fabrics is reviewed. This work shows that, when laboratory-controlled practical washing and home laundering are com-pared, good correlation can be obtained although washing in the home was generally poorer than in the laboratory. Large losses in reflectance oc-cur on certain fabrics in some families in the home-laundry study. Polyester-containing fabrics tend to gray by redeposition more than other fabrics investigated. The new permanent-press fabrics seem more susceptible to redeposition than their untreated substrates, from which they are derived. A systematic screening of factors af-fecting the performance of these fabrics in the laundry indicates that detergent under-usage is a major factor for the failure of polyesters to perform as well as cotton. Laboratory-scale deter-gency and redeposition studies agree with the practical experiments. Further work on the relation of chromatic changes on this same group of fabrics is also re-ported. The blue-yellow scale was found to be extremely important in its effect on ultimate visual preference of the fabrics in this study. A unit change in apparent yellowness was found to be more than four times as important as a unit change in grayness in determining visual preferences. It was also shown that fabrics of a yellow hue were subjectively unsatisfactory to a panel of judges whereas fabrics with a blue-white hue caused by brighteners tended to be acceptable irrespective of their grayness within reasonable limits. Thus optical brightener effects, or lack of them, appear to be the single most important detergent-related factor in determining the laun-dered appearance of these fabrics.

The presence of cells or colonies of yeasts in polluted water, sewage, and sewage-treatment processes may have been anticipated by some workers dealing with the biology of such habitats, but little has been said about them in the literature. Cake yeast has been used in the starting of septic tanks, activated-sludge systems, and sludge digesters, but whether brewer's or baker's yeast was more effective or effective at all is unknown. Heukelekian (1942) set up a series of experiments with cake yeast, using a brand of baker's yeast supplied by Anheuser Busch Co., adding it to sewage in open and closed vessels, and to a ripe sludge mixture. He concluded that "(1) yeast does not hasten the stabilization of sewage under anaerobic conditions," and "(2) yeast does not hasten the digestion of seeded sludge mixtures." In 1953 Heukelekian again reported on an experiment in which baker's yeast was used to determine the effect of this type of biological preparation on the digestion of sewage solids. He concluded that "the addition of . . yeast does not increase the liquefaction of non-sterile fresh solids as measured by the B.O.D. of the supernatant liquor," although during the experiment some gas was formed and solids were reduced to some extent. That no recovery was made of either baker's or brewer's yeast from samples tested for fungi, in the series of isolations on which this report is based, may result from an error in sampling technique, from incomplete sampling due to use of incorrect enrichment medium, or from a habitat not conducive to the survival of these species of Saccharomyces. In screening various polluted habitats for their potential fungus popu

Four types of artificially-soiled cloths are compared in their ability to evaluate cleaning of representative detergent products. Three of these cloths are commercially available while the fourth is from a private laboratory. These are compared in their ability to rate detergents in the same order as naturally-soiled clothes rate detergents. Sensitivity and reproducibility of the various soiled cloths in measurement of soil removal and whiteness retention are studied.

Oxygen respiration was studied in bovine pulp slices exposed to temperatures of 50, 55, 80, and 100C. Results indicated that respiration is affected at 50C and destroyed at 55C. The significant but subnormal oxygen consumption measured in tissue heated at 80 and 100C is thought to be caused by autooxidation.

This study shows the buffering limitations of Krebs-Ringer-phosphate solution in the presence of acid production by dental pulp and indicates the need for appropriate selection of suspending fluid volume and tissue sample mass in reaction vessel loads.

Assessment of oil quality by two accelerated oxidation tests gave little or no correlation with organoleptic asessment during storage. Improvements in quality of oils refined in the factory, to which antioxidants had been added, are indicated by the accelerated tests but are not reproduced in normal storage. Howver a treatment of the oils with alumina, as a part of the refining process replacing earth bleaching, appears to remove antagonistic factors, and under these circumstances the addition of antioxidant has a pronounced effect.

Antimicrobial agents were used in the water coolant system in the high-speed dental drill during a series of tooth preparations on a model. Artificial saliva was applied to the dentition before the procedure began. For five minutes after cessation of drilling, the aerosols generated were collected on precipitation plates. Six agents reduced the bacterial counts to levels less than that recorded for water alone.

A new process has been developed, in which the cyclopropenoid groups in cottonseed oil can be selectively and continuously hydrogenated under mild conditions. This process utilizes nickel in a fixed-bed reactor, thereby eliminating the ex-pensive filtration commonly associated with slurry reactors.

There is a growing need for high throughput diagnostic tools for early diagnosis and treatment monitoring of prostate cancer (PCa) in Africa. The role of cancer-testis antigens (CTAs) in PCa in men of African descent is poorly researched. Hence, we aimed to elucidate the role of 123 Tumour Associated Antigens (TAAs) using antigen microarray platform in blood samples (N = 67) from a South African PCa, Benign prostatic hyperplasia (BPH) and disease control (DC) cohort. Linear (fold-over-cutoff) and differential expression quantitation of autoantibody signal intensities were performed. Molecular signatures of candidate PCa antigen biomarkers were identified and analyzed for ethnic group variation. Potential cancer diagnostic and immunotherapeutic inferences were drawn. We identified a total of 41 potential diagnostic/therapeutic antigen biomarkers for PCa. By linear quantitation, four antigens, GAGE1, ROPN1, SPANXA1 and PRKCZ were found to have higher autoantibody titres in PCa serum as compared with BPH where MAGEB1 and PRKCZ were highly expressed. Also, p53 S15A and p53 S46A were found highly expressed in the disease control group. Statistical analysis by differential expression revealed twenty-four antigens as upregulated in PCa samples, while 11 were downregulated in comparison to BPH and DC (FDR = 0.01). FGFR2, COL6A1and CALM1 were verifiable biomarkers of PCa analysis using urinary shotgun proteomics. Functional pathway annotation of identified biomarkers revealed similar enrichment both at genomic and proteomic level and ethnic variations were observed. Cancer antigen arrays are emerging useful in potential diagnostic and immunotherapeutic antigen biomarker discovery.

SYNOPSIS IN INTERLINGUA ANALYSE DEL PORTION ORGANIC DE CALCULO DENTAL.—Specimens de composite e de separate calculos supra- e subgingival e de calculos ab dentaturas esseva decalcificate per le uso de 0,1 N de HCl e de un solution de 15 pro cento de tetraacetato ethylenediaminic a un pH de 7,0 a 7,5. Analyses chromatographic del hydrolysatos acide monstra que le mesme amino-acidos compone le portion proteinic del calculos supragingival como del calculos subgingival. Le aminoacidos trovate in mucina precipitate es simile a illos presente in calculos salivari. Le fraction carbohydratic del matrice organic del calculos esseva studiate per chromatographia a papiro. Galactosa, glucosa, mannosa, rhamnosa, e fucosa esseva detegite. In plus, il pare esser presente un hexosamina, un deoxy-sucro, e un acido sialic.

Four types of steel were tested, using dental instruments, for changes in hardness as a function of sterilization or disinfection. Steam autoclave, dry heat sterilization, and chemical disinfection were used. Knoop hardness was determined at intervals and data were statistically analyzed. Significant loss of hardness was observed in specific instances.

Domestic tung oil is a very uniform product as shown by the determination of the chemical and physical properties of 74 samples taken over three successive milling seasons.

A high-rate municipal compost system was systematically sampled during the digestion period for the presence of thermophilic fungi. Pure cultures of 304 isolates were established which included: As...

Homogenized and centrifuged mycelial extracts of Arthrobotrys musiformis, suggested the presence of a nematode attraction substance(s) after the fungus had developed predaceous structures. Initial ...

Two characteristics clearly distinguish between the dentitions of typical mammals and reptiles: generally the former are heterodont and diphyodont while the latter are homodont and polyphyodont. Superficially it might seem that by progressively reducing the number of replacement teeth in an evolutionary sequence of animals, it was a simple matter to arrive at a diphyodont mammalian descendant from a polyphyodont reptilian ancestor. But data on the sequences in which teeth are initiated in mammalian and reptilian embryos suggest that the process was more complex. In most reptilian embryos teeth are probably developed in sequences which pass through alternate positions from the back to the front of the jaw (Osborn, 1971). It is not easy to relate this sequence to that observed in mammalian embryos; for instance for the upper jaw of Eremnitalpa, Osborn (1970) gives the sequence it, i2, C, m4/M1/m3/i3/M2/M3/I1, 12, C, P3, P4/ 13 (in which the lower case represents deciduous teeth and the sequence is known only where bars separate teeth). Both heterodonty and a very limited number of replacement teeth also evolved in the postcanine dentitions of the gomphodont cynodonts and their descendants, the tritylodonts of the Triassic and Jurassic (Crompton, 1973). Although these animals finally become extinct in the middle Jurassic, it seems possible that the manner in which they evolved their limited numbers of replacement teeth from the ancestral polyphyodont condition might shed light on the evolution of diphyodonty in mammals. The earliest of the well-known gomphodont cynodonts with a markedly heterodont postcanine denition and a linited number of replacement teeth was Diademodon. The purpose of the present paper is to plot the sequence in which postcanine teeth were replaced in Diademodon and to compare this with tooth replacement in a polyphyodont reptilian dentition. If both have been correctly understood it should indirectly be possible to obtain some idea of the biological controls which regulate tooth replacement. And it can be safely assumed that by varying similar biological controls, mammalian diphyodonty could also have been evolved from polyphyodont dentitions. The pattern by which Diademodon, a lower Triassic gomphodont cynodont, replaced its postcanine teeth has recently been studied by Crompton (1963), Ziegler (1969) and Hopson (1971), and is also referred to by Crompton (1973). In view of the fact that no new data is provided in the present paper, it might seem unnecessarily contentious to propose a fourth solution to this problem within eight years. However, during the last decade almost all workers have, with varying degrees of success (e.g., DeMar, 1972) attempted to fit patterns of tooth replacement into the framework of a general model known as the Zahnreike theory. This theory, which was proposed by Edmund (1960, 1962), apparently links together tooth replacement patterns encountered throughout the vertebrate kingdom. My own studies, referred to above and later, have convinced me that the Zaknreike theory as a model describing the initiation of patterns of tooth replacement is untenable in the face of the phylogenetic and embryological evidence. I have concluded that the rate of tooth replacement is partly controlled at each tooth position.

This paper is based on a study of the variation and covariation of 18 morphological characters of the aphid, Pemphigus populi-transversus Riley, from 23 localities in eastern North America. The variation and covariation of these characters are separately studied within galls, among galls within localities, and among localities. By means of factor analysis, covariation is restated in terms of fewer dimensions (factors). The factors are compared at the different levels of variation. This paper continues an earlier study (Sokal, 1952) in which the author examined 21 characters of a single population of this gall-forming aphid from Ripley, Ohio. Of this local population, 28 galls containing four alate aphids each were studied. Since the alates within any one gall are isogenic and the different galls presumably represent different genotypes, the variance of the characters could be partitioned into a non-hereditary, intragall portion and an intergall portion which is assumed to be partly genetic and partly environmental in origin. Several characters, representing independent dimensions of intergall variation, were chosen by analysis of covariance. The purpose behind this procedure was the recognition of fewer than the original number of characters for a further study of intraspecific variation. Three problems emerged concerning the use of the characters chosen by the previous analysis. The first is the possibility, suggested by Clark's (1941) findings on Peromyscus, that the intergall correlations on which the former study is based might vary geographically, thus presenting a different pattern of significant characters in other areas. Average intergall correlations for many localities are therefore computed below. The second problem is whether some characters lacking intergall variance in the Ripley population might yet possess significant interlocality variance. As will be seen below, this proved to be the case for several meristic characters. Thirdly, and most important, are the characters representing genetic and environmental differences among galls necessarily the same as those describing genetic and environmental differences among localities? This study will show that there are real differences between interlocality and intergall factor patterns. As the study progressed a number of other objectives came into view, and assumed progressively increasing importance. The unusual hierarchic structure of the data at hand (isogenic alate aphids descended from a single stem mother, morphologically distinct but genetically identical, all contained within an individual gall; galls putatively representing different genotypes found within one locality; and finally localities presumed to differ genetically from each other) permitted a detailed and quantitative separation of sources of variation in this study. Since correlations can be computed at each of these levels of covariation, the differences between these correlation matrices and between the factors into which they were resolved eventually, provide a novel Part 2 of a study of variation in the aphid genus Pemphigus. Part 1 is Sokal (1952), part 3 is Sokal and Rinkel (1962). 2 Contribution No. 1125 from the Department of Entomology of The University of Kansas, Lawrence, Kansas.

Enterobryus is one of the genera of commensal fungi belonging to the order Eccrinales, and, like all members of the order, its species have been found living only within the hindguts of arthropods. While the sexual nature of species within the Eccrinales has not been clearly established, their vegetative characteristics suggest possible affinities with the Phycomycetes, for the hyphae are coenocytic, non-septate, and the presence of cellulose can be demonstrated in the cell walls. Enterobryus attenuatus, one of five species described by Joseph Leidy between 1849 and 1853, is of particular interest because it was discovered in the hindgut of a beetle, Passalus cornutus Fab., rather than in millipeds as were the other species found by Leidy. This host difference has led some authors to make a generic separation of those species found in beetles from those found in millipeds, a matter which will be discussed later in this paper. E. attenuatus was first described in a paper presented by Leidy in 1849(b), though mention of this species had been made in a paper published earlier that same year (1849a). A more complete description with drawings appeared in 1853. I have collected specimens of Passalus cornutus and have studied the fungi associated with them. Hyphae of the fungus which Leidy discovered were seen in all individuals, and were found to be substantially as Leidy described them. However, in the most anterior region of the hindgut of all host specimens dissected I also found other hyphae which, upon first examination, appeared to be quite different from those described by Leidy, but it is my belief that they represent another phase of the fungus, Enterobryus attenuatus, apparently not observed by Leidy. It is the purpose of this paper to present a description of these new hyphal types and the spores they produce, and to suggest how they fit into the life cycle of the fungus.

In previous papers, experimental studies of the effectiveness of mimicry in two groups of North American butterflies have been described (Brower, 1958a & b). The present paper is an investigation of presumed mimicry in Danaus gilippus berenice (Cramer), model, and Limenitis archippus floridensis (Strecker), mimic, sometimes called the Queen and the Florida Viceroy, respectively. The mimetic relationship between these two butterflies first was noted by Scudder (1870), but D. g. berenice and L. a. floridensis have received less attention in the literature than their close relatives the model and mimic, Danaus plexippus (Linne), the Monarch, and Limenitis archippus archippus (Cramer), the Viceroy. Poulton (1909) has stated that there is no reason to suppose that the palatability of D. g. berenice to predators

In studying the evolutionary dynamics of polymorphisms in natural populations, most of the work in the past has concentrated on single genetic entities. The Work of Dobzhansky and his collaborators on the inversion sequences in the third chromosome of Drosophila pseudoobscura, the studies of Lamotte (1951) on shell color and banding in the snail Cepaea nemorallis, and those of Allison (1955) on abnormal hemoglobins in man are examples of genetic studies of polymorphisms controlled by alleles at a single locus, or else by blocks of genes which act in heredity as single loci. A new order of complexity is introduced when an attempt is made to study simultaneously two or more segregating systems in the same population because of the possibility, indeed the probability, that the evolutionary fates of the different polymorphic systems are not independent. Such will be the case if there is interaction between the different loci in the determination of the fitness of various genotypes. For example, the fitness of individuals of the genetic constitution AA may be greater than those with the constitution aa if at a second locus these individuals are, let us say, BB; but this fitness relationship may be reversed in the presence of bb at the second locus. In such cases the polymorphisms A,a and B,b are not independent in their fates in the population. Levitan (1955, 1958) in his studies of the inversion polymorphisms of Drosophila robusta has evidence of a small interaction of this sort and Cain and Sheppard (1954a, 1954b) have found such interactions for shell color and banding in Cepaea nemoralis. One of the most favorable materials for the study of these interactions and their evolutionary consequences is the Australian grasshopper, Moraba scurra. In an earlier paper (White, 1957) evidence was presented that the pericentric inversions, carried on two different chromosome pairs in this species, are not combined at random in the adult male individuals of certain natural populations. The deviations from random combination were regarded as proof of a genetic interaction between the two systems of cytological polymorphism, so far as their effects on viability are concerned. The significance of this interaction effect has been discussed and a hypothesis as to how it could have arisen has been suggested (White, 1958). The present paper has two purposes. First we shall present added data on the interaction effect from recent collections. The data published previously relate to six adult male samples collected in 1955 and 1956 at various localities in South Eastern Australia. Further data on two of these populations (at Wombat, New South Wales, and Royalla "B," Australian Capital Territory) were obtained in 1958 and 1959. Statistical analysis of the more recent data provides

For evident reasons, field studies of the population ecology of rare or sparsely distributed animals are almost nonexistent. Less easily explicable is the dearth of theoretical papers concerned with ecological factors which may come into play for sexually reproducing species at low density. Andrewartha and Birch (1954:333, 337-43) state the lack of studies of "underpopulation," noting possible reduction of the innate capacity for increase because of the failure to find mates. They give a detailed discussion of mate-finding in the sheep tick, Ixodes ricinus, based on work by Milne. They also discuss briefly (op. cit.: 695-697) possible effects, at population low, on genetic composition in a fluctuating population. Since their work, Philip (1957) has presented a study of population growth (or extinction) based on analysis using the probability of fertilization of females in a random model in combination with the logistic curve. Numerous papers presented by Wright (e.g., 1931, 1940, 1948) have noted the relative importance of random fluctuations in gene frequency (as opposed to changes in frequency due to natural selection) in populations with small effective population size. Summaries of the evolutionary significance of Wright's work can be found in Dobzhansky (1951) and in Li (1955). Pertinent to this study are Wright's conclusions as to the importance of populations of small effective size in evolution. Thus Wright (1931:157)

It has long been accepted by students of the genus Gossypium that the New World cottons (G. hirsutum L., G. barbadense L., and G. tomentosum Nutt.) are natural amphidiploids combining an A genome from a taxon of the Asiatic diploid group and a D genome from a taxon of the American diploid group (Skovsted, 1937). Beasley (1940b) and Harland (1940) provided confirming evidence on the origin of the New World type by synthesizing amphidiploids from A x D hybrids that were similar in morphology and cytogenetically compatible with the natural amphidiploids. More recent research on the general question of the origin of New World cottons has been directed toward pinpointing the taxa that were involved in the original hybrid and to the problem of "when" and "how" they were brought together so that hybridization could take place. These two questions form the basis of this paper, and they will be treated in turn. Triploid hybrids of New World (genome formula, AD) x Asiatic (A) and New World x American (D) show 13 II and 13 I at metaphase I (MI) of meiosis (this evidence supported Skovsted's hypothesis of amphidiploid origin). But since each of the two AD x A triploids and all of the seven possible AD x D triploids show essentially the same number of bivalents at MI, there is little basis here for identifying the parents of the New World amphidiploid. A method described by Stephens (1950) and used extensively in this laboratory (see review in Phillips, 1962) takes advantage of the segregation frequencies of marker genes in synthetic allohexaploids to discern interrelationships among the A, D, and AD taxa. A brief summary of the results of these studies (Gerstel, 1956; Gerstel and Phillips, 1957; Phillips and Gerstel, 1959; Phillips, 1962) appears in table 1. The relationships indicated in the table show that G. herbaceum and G. arboreum are very closely related to the taxon that contributed the A genome to New World cotton and that G. raimondii is rather closely related to the contributor of the D genome. The "gap" in this picture is the absence of the cross AD x D3 from table 1. Neither G. klotzschianum Andersson (D3-K) nor G. davidsonii Kellogg (D3-D), which some students of the genus consider to be conspecific, can be successfully hybridized with any of the New World species, and they will form vigorous hybrids with only two other species in the genus (G. anomnalum Wawra and Peyr. and G. longicalyx Hutchinson and Lee). There is thus no "direct" genetical or cytological method for assessing the relative chromosome homologies of D3 and DnW (D genome of New World cotton). However, by means of a bridging-species hybrid, the D3 and DnW genomes have been brought together in the same hybrid and their homologies compared by assessing chiasma frequency. By comparing chiasma frequency in this hybrid with that of a similar hybrid combining D5 and D,wy 'Contribution from the Crop Science Department, North Carolina Agricultural Experiment Station, Raleigh, N. C. Published with approval of the Director of Research as Paper No. 1509 of the Journal Series and with approval of the Crops Research Division, Agricultural Research Service, U.S.D.A.; supported in part by Project S-1 of the Research and Marketing Act of 1946. Aided by grant G-14203 of the National Science Foundation. 2 The genome nomenclature used in this paper follows Beasley (1940a and 1942) and Brown and Menzel (1950 and 1952).

A key to the genera of the Dacrymycetaceae and a taxonomic discussion of the various genera, including Dacrymyces, may be found in the preceding paper (Kennedy, 1958). There the methods employed in the study of these fungi and the terms used in the descriptions were explained. When Nees established the genus, which he spelled Dacryomyces, in 1816, he described the sporocarp as a fleshy or gelatinous substance, round or discoid in form, bright yellow or red in color and composed of interwoven filaments with spores. It included one species, Dacryomyces stillatus. Fries, in 1822, added to the description the characteristics of homogeneous consistency and spores formed on all sides of the sporocarp. Since then the boundaries of the genus have exhibited great flexibility, expanding or contracting according to the number of other genera recognized for the family. For example, in Neuhoff's (1936) treatment Dacrymyces, while not defined, includes at least species belonging to the genera Ditiola, Guepiniopsis and Femsjonia, and one gains the impression that he would place species of nearly all the genera but Calocera there. On the other hand Martin's (1952) concept is much narrower, because of the recognition of ten other genera in the family. The concept of the genus presented in this paper was arrived at by defining eight other genera for the Dacrymycetaceae. Such a procedure leads to a view of the genus Dacrymyces which is somewhat negative in nature, for one thinks of it as a group of species that does not fit the pattern of the other, more easily defined, genera. Thus we find that, except for allowance of considerable variation in external basidiocarp form, the present description differs little from that of Fries. Dacrymyces still includes the largest number of species but seems now to comprise a natural group. 1 Based on Part II of a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in the State University of Iowa